Pharmaceutical products with histamine H3 receptor ligand properties and subsequent pharmacological activities thereof are described in EP-980300. An especially important product among those disclosed is 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine. This compound is disclosed as the free base and as the oxalate salt.
The use of 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine as the free base is limited because of its oily nature. On the contrary, 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine oxalate is a crystalline substance but its low aqueous solubility (0.025 g/ml at 23° C.) also limits its use as a pharmaceutical ingredient.
Subsequent patents EP-1100503 and EP-1428820 mention certain salts of 1-[3-[3-(4-chlorophenyl)propoxy]propyl]-piperidine. However, the only one specifically described is the oxalate salt. The crystalline monohydrochloride salt is not described.